Conventionally, biometric authentication apparatuses that perform authentication by imaging biological information such as veins of the palm, or the like are known.
For a fingerprint matching device, one of such biometric authentication apparatuses, a configuration where a cover is attached to a case by engaging an engagement portion of the cover with that of the case is known (for example, see Japanese Laid-open Patent Publication No. 2001-256487).
As the configuration of the engagement portion, a stopper that is used for a wiring process structure of a washing machine and that sandwiches a substrate between a unit case and the stopper is known (for example, see Utility Model Registration No. 2534827).